Lubrication



Patented Oct. 30, 1945 UNITED STATES 4 PATENT OFFICE LUBRICATION No Drawing. Application April 26, 1943, Serial No. 484,608

11 Claims.

This invention relates as indicated to lubrication and more particularly to the provision of a lubricating composition capable of withstanding greater pressures per unit area. before seizure and scoring of the bearing surfaces takes place than such pressures as a pure mineral oil may. for example, withstand.

It is a more particular object of this invention to provide a lubricating composition which is of such nature that it will react with the bearing surfaces in such manner as to be particularly effective for use under conditions resulting in thin film lubrication which maintain when the pressure between the bearing surfaces is in the neighborhood of or in excess of approximately 10,000 pounds per square inch.

It is a further object of this invention to provide a lubricating composition and a method of improving the lubricating properties of a lubricating oil such as pure mineral oil particularly to increase the break-down pressure of the film of such oil between bearing surfaces, and consequently to improve the thin film" lubricating characteristics of the oil.

Other objects of the invention will appear as the description proceeds.

Our invention, then, consists of the steps hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain steps embodying the invention, such disclosed steps constituting, however, but one of the various ways in which the principle of the invention may be used.

The present invention contemplates the provision of a lubricating composition which contains organic derivatives of inorganic oxy-acids, such compounds being used with or without being admixed with a suitable oil base such as a mineral oil.

Where the lubricating composition in accordance with the present invention comprises such admixture, the components thereof may, as previously indicated, be broadly classified as the oil base and the addition agent.

The oil base The suitable oil base comprising one of the components of the lubricating composition of the present invention may be any suitable lubricating oil such as a mineral or vegetable oil or any suitable oil usable for purposes of lubrication. Furthermore, this invention contemplates the use as lubricating oil base of oils generally which may have been subjected to a particular treatment for the purpose of imparting thereto characteristics not originally possessed thereby and which render the same particularly suitable or in any event do not render them harmful for use as lubricants.

Addition agents asmuch as lubricating oils may on occasion be subjected to elevated temperatures the more stable of such compounds are preferred. It will be found that such compounds of the class enumerated as having a boiling point of over 140 C. or at most 170 C. will be best suited for the purpose in contemplation for the reason that they will not be volatilized and lost from the composition should the same in use, for example, be subjected to an elevated temperature. For certain uses, however, where elevated temperatures are not encountered, compositions having a lower boiling point than those above indicated will be found satisfactory.

It is believed that the above identified 'broad class of compounds contemplated for use by this invention and generically defined as organic derivatives of inorganic oxy-acids may be conveniently classified in the following manner, viz:

I. Classification according to nature of acid from which compound is derived. Compounds may be derivatives of:

Sulphuric acid Carbonic acid Sulphurous acid Nitric acid Nitrous acid Oxyhalogen acids, e. g.: (a) Hypochlorous (b) Chlorous (c) Chloric (d) Perchloric '7. Cyanic acid mounwzo effect. On these cases it may be advisable to use a compound which may be too unstable or of too con'osive a nature, for ordinary applications.

The exact mechanism by' which "addition agents, contemplated for'use by the present invention, are effective in increasing the film strength of lubricants is not clearly understood, but it has been suggested that certain elements, or groups of elements, may react with the metal atoms of the bearing surfaces, due to the stress of the rubbing action under severe conditions. The metal-bearing compounds so produced may then act to prevent actual contact of the metal surfaces, and may thus exert an "anti-fluxing action capable of inhibiting the welding together of' a part of one surface with a part of the other. It is assumed that scoring usually results from the tearing apart of such welded portions of the two surfaces.

The compounds contemplated by this invention as addition agents contain acid radicles, or acid-forming groups and are, therefore, capable of reacting with metals to form such anti-fluxing materials under the conditions assumed by the theory above described.

Certain addition agents seem to be capable of improving the lubricating qualities of a lubricant in another way, that is by increasing the "oiliness of the lubricant, or its ability to reduce friction. These materials appear to have in common the tendency to be strongly adsorbed by metal surfaces. Such a tendency is characteristic of oxygen-bearing compounds-in general, and particularly those which are of an acid, or acidforming character. It would, therefore, appear that the addition agentsof this invention are particularly well adapted for this purpose.

The halogen-bearing compounds of the type contemplated are particularly effective because of the presence of two separate means which may act to produce anti-fluxing materials, viz.: the halogen, and the acid group. In addition, the presence of oxygen in the acid group, because of its tendency to be strongly adsorbed on metal surfaces, increases the eifective concentration of the active ingredients at the bearing surfaces where they may function as required.

' Range of compositions As previously indicated, this invention contemplates the use of a lubricating composition of the so-called addition agents either singly or in combination with other addition agents and/or a suitable oil base. When used alone, the halogen-bearing compounds are usually preferred of which the following are notable examples:

Di- (B-chlor-ethyl) sulphate Di-(o-chlorbenzyl) sulphite Di- (dichlor cresyl) carbonate Chlorbenzyl nitrate Nitroso-chlorbenzene Chlorbenzyl cyanate For ordinary types of lubrication such as in the crankcase of internal combustion engines, it has been found that the two considerations which determine the amount of the addition agents which is to be added to a lubricating oil are, first, the cost of the resultant composition, and, second, the reduction of viscosity of the lubricating composition as a result of the presence of the addition agents. i

It has been found that very satisfactory results, i. e., a lubricant capable of fulfilling all of the requirements incidental to ordinary use may be secured by the employment, of addition agents in amounts less than about 20%. The addition agents when present in amounts of5% and less have been found to remarkably increase the extreme pressure characteristics of lubricating oils. Certain of the more active compounds may be entirely effective for ordinary purposes when present in the amounts as low as fractions of 1%.

As hereinafter referred to, lubricating compositions in accordance with the present invention are particularly useful when added to gasoline and like motor fuels for the purpose of affording lubrication to valves and like parts not normally fully lubricated by the oil in the crankcase of the engine and are also effective to keep down and reduce carbon deposits in the combustion chamber. When the lubricating composition is employed for this last-named purpose, 1. e., when added to a gasoline or similar motor fuel, the percentage of addition agents present therein may be considerably higherthan when the composition is used in the crankcase. accordance with the present invention and designed to be added to a fuel may contain up to of the so-called addition agents, and certain of such addition agents, notably those which are halogen bearing may be used in their pure state.

Uses and advantages In addition to theadvantages attained by the use of. certain products contemplated by this invention to increase the film strength of lubricating oils or as lubricants possessing "high film strength, other advantages may be obtained as follows. The compounds are in general relatively stable and therefore resistant to the composition oxidizing and to gum forming and sludge forming reactions, especially when used as crankcase lubricant in internal combustion engines. Certain of the compounds named are effective when present in mineral lubricating oil compositions to reduce the rate of change of viscosity with the temperature and usually have a tendency to prevent precipitation of crystalline or gelatinous materials, such as waxes, on chilling. Lubricants resulting from the use, either pure or mixed with other lubricating oils, of such products, therefore have the advantage of improving viscosity index and lowering pour point.

As previously indicated, the lubricating compositions made in accordance with the present invention are particularly applicable for use generally under high temperature and extreme pressure conditions which makes them particularly suitable for use as lubricants added to a, fuel which passes directly into the combustion chamber.

It has been found that certain of the compounds above described either alone or in combination with other materials such as lubricating oils are capable of reducing the rate of wear of the bearing surfaces, particularly during thin film lubrication, and especially when one of the bearing surfaces is of a so-called bearing metal type such as babbitt, brass and bronze.

This application is a continuation-in-part of our copending application, Serial No. 14,295, filed A lubricating composition in April 2, 1935 now Patent No. 2,340,331, dated Feb. 1, 1944.,

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

We, therefore, particularly point out and distinctly claim as our invention:

' 1. A liquid extreme'pressure lubricant for use in the crankcase of internal combustion engines comprising mineral lubricating oil and an amount of an addition agent comprising a sulphur-tree organic derivative of carbonic acid sufiicient to increase the load carrying capacity of the mineral lubricating oil so as to prevent seizure and scoring 01' bearings'lubricated thereby when operated underpressures of at least 10,000 pounds per squar inch.

2. A lubricant comprising a major proportion 01' lubricating oil and a minor proportion of an organic halogen-bearing derivative of carbonic acid sumcient to increase the load carrying capacof lubricating oil and a minor proportion of a halogen-bearing ester or carbonic acid sufllcient to increase the load carrying capacity of the mineral lubricating oil so as to prevent seizure and scoring of bearings lubricated thereby when operatcd under pressures of at least 10,000 pounds per square inch.

5. A liquid extreme pressure lubricant for use in the crankcase of internal combustion engines comprising mineral lubricating oil and an amount of an ester of normal carbonic acid suflicient to increase the load carrying capacity of the mineral lubricating oil so as to prevent seizure and scoring of bearings lubricated thereby when operated under pressures of at least 10,000 pounds per square inch.

6. A liquid extreme'pressure lubricant for use in the crankcase of internal combustion engines comprising mineral lubricating oil and an amount oi. an aromatic ester otnormal carbonic acid sui'- flcient to increase the load carrying capacity of the mineral lubricating oil so as to prevent seizure and scoring of bearings lubricated thereby when operated under pressures of at least 10,000 pounds per square inch.

7. A liquid extreme pressure lubricant for use in the crankcase of internal combustion engines comprising mineral lubricating oil and an amount of an alkyl ester of normal carbonic acid sufficient to increase the load carrying capacity of the mineral lubricating oil so as to prevent seizure and scoring of bearings lubricated thereby when operated under pressures of at least 10,000 pounds per square inch.

8.;A liquid extreme pressure lubricant for use in the crankcase of internal combustion engines comprising mineral lubricating oil and an amount of a dialkyl ester of normal carbonic acid suillcient to increase the load carrying capacity of the mineral lubricating oil so as to prevent seizure and scoring of bearings lubricated thereby when operated under pressures of at least 10,000 pounds per square inch.

9. A liquid extrem pressure lubricant for use in the crankcase or internal combustion engines comprising mineral lubricating oil and an amount of di-(o-chlorphenyl) carbonate sufiicient to increase the load carrying capacity of the mineral lubricating oil so as to prevent seizure and scoring of bearings lubricated thereby when operated under pressures of at least 10,000 pounds per square inch.

10. A liquid extreme pressure lubricant for use in the crankcase of internal combustion engines comprising mineral lubricating oil and an amount or di(B-chlorethyl) carbonate suilicient to increase the load carrying capacity of the mineral lubricating oil so as to prevent seizure and scoring 0! bearings lubricated thereby when operated under pressures of at least 10,000 pounds per square inch.

11. A liquid extreme pressure lubricant for use in the crankcase of internal combustion engines comprising mineral lubricating oil and an amount of di-lauryl carbonate sufficient to increase the load carrying capacity of the mineral lubricating oil so as to prevent seizure and scoring of bearings lubricated thereby when operated under pressures of at least 10,000 pounds per square inch.

AMOS T. KNUTSON. ELDON F. GRAVES. 

